Will a 01- Denali headlight work in a 00 Sierra? It was my understanding that the headlights did not change over the years....even in 03.:confused::confused::confused:

Is there a diff in 01? If there is, then no, if its the same then yes. Overall, Denali's headlights DO fit in the GMC's. Do a search for "Denali Projector" and you'll find some huge threads